A navigation device having a map display function is provided with a path search function of searching for the shortest distance from a current location to a destination, or for the shortest time in consideration of dynamically changing traffic information. A method of setting a destination to be set for the path search at first includes a method of setting the destination directly with the use of a telephone number of a fixed telephone. An example is that the location of the destination is determined from the telephone number of the fixed telephone that has been installed at the destination (hereinafter, this method is referred to as “telephone number input method”).
In such a telephone number input method, a user inputs a telephone number via input means such as a touch panel or the like equipped in a navigation device. A memory device such as a CD-ROM, DVD-ROM, or the like equipped in the navigation device stores the telephone number of the fixed telephone and location information of where the fixed telephone is located, and name information, facility information, address information, messages, images as attribute information of the telephone number (hereinafter, those pieces of information will be referred to as “guide information”), and area code and local number and the relationship of representative location information of the area that the number.
Then, the guide information is searched for from the telephone number input by the user. In this situation, if there is a telephone number, stored in the guide information, that matches the telephone number input by the user, the location information will be read out from the guide information to determine the location of the destination (for example, see Patent Document 1).
Conversely, if there is no telephone number, stored in the guide information, that matches the telephone number input by the user, the representative location information of the area that the area code and local number included in the telephone number cover will be searched for. In addition, a map with the representative location being centered is displayed, so that the user scrolls the map to determine the location of the destination.
Alternatively, if there is no telephone number, stored in a user portable navigation device, that matches the telephone number input by the user, there is a method of inquiring at a database server residing on a communication network to acquire the location information (for example, see Patent Document 2).
By use of such a telephone number input method, it will be made possible to set a destination, only if the telephone number of the fixed telephone installed at the destination is known.
Meanwhile, in addition to the fixed telephone, there is a navigation device that enables a path search for a destination by acquiring location information of a mobile communication terminal and setting it as the destination (for example, see Patent Document 3).